docs: def execd_module_paths(execd_dir=None):
      """Generate a list of full paths to modules within execd_dir."""
      if not execd_dir:
          execd_dir = default_execd_dir()
  
      if not os.path.exists(execd_dir):
          return
  
      for subpath in os.listdir(execd_dir):
          module = os.path.join(execd_dir, subpath)
          if os.path.isdir(module):
              yield module